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Economic impact of reproduction

Approximately 50% of the profit per lactation is generated in the first 100 days of lactation. During this period the return per feed dollar is usually 3:1 in contrast to late lactation when it is approximately 1:1. A goal of the reproductive management program should be to have the cow spend as much of her life in the early phase of lactation as possible. Thus, it is critical that the reproductive management program focus on getting a large percent of the cows pregnant quickly after the voluntary waiting period (VWP) so that the majority of the cows will spend a sufficient proportion of their lives in early lactation. We derived equations and obtained estimates of financial benefits for various pregnancy rates (PR) with interactions of milk yield, calving, culling for reproductive failure and days open. Improvement in milk production due to reduction in days open was dependent on days in milk, peak milk production, and monthly rate of decline in daily milk. Costs per day open were calculated to be $0.50 for 100 days, $1.42 for 130 days, $2.99 for 160 days and $4.52 for 175 days. A comparison of a visual heat detection program (16% PR - approximate average for DHI herds in Virginia) with three commonly used synchronization protocols (OvSynch, PreSynch, and HeatSynch) revealed the following. Unadjusted cost per pregnancy (out of pocket cost) was lowest for the visual heat detection program at $55.40 with the three synchronization protocols ranging from $78.59 for PreSynch to $69.87 for HeatSynch. The number of reproductive culls showed an advantage to the synchronization protocols with visual heat detection resulting in a 10.8% cull rate or 37 or the 250 cows not pregnant by 300 days in milk. In contrast, the three synchronization protocols had a similar culling rate of 6.4% or 16 of the 250 original cows failing to conceive by 300 days in milk. The adjusted cost per pregnancy which included cost of extended days in milk and cows removed because of failure to conceive by 300 days was $298.35 for the visual heat detection program, $123.46 for HeatSynch, $115.39 for OvSynch and $110.49 for each pregnancy obtained using the PreSynch protocol. OvSynch protocol developed in the mid-90's allowed for the first timed artificial insemination (TAI) program that obtain conception rates similar to those of cows artificially inseminated to detected estrus. Modifications of the OvSynch protocol to maximize cows between day 5 and 12 of the estrous cycle (PreSynch) have shown a further enhancement in conception rates to TAI. HeatSynch is a less expensive alternative to PreSynch; however, it requires heat detection and may not work in anovulatory cows. For best results, visual heat detection should be conducted between initial synchronization on first service and resynchronization of cows not detected 18 to 24 days post AI. Pregnancy diagnosis at 33 days allows for accurate determination without a high early post detection embryonic death loss experienced with earlier ultrasonic imaging. All three protocols reduced days open and increased PR with no significant economic advantage of one protocol over the other.